This invention relates to animal watering devices, and, more particularly, to inverted bottle watering devices for on-demand watering in animal enclosures.
Animal watering devices were initially developed as a means for tending caged laboratory animals in a cost-effective manner. A common design that has evolved includes an inverted bottle having a depending outlet spout, and some form of metering device that emits water when touched or licked by the animal. Often, the bottle is secured to the exterior of a wire cage or the like, and the depending spout extends obliquely through the cage wall to be accessible to the animal.
The most widely used metering devices employ some form of mechanism in which a ball is secured in the lower end opening of the outlet spout to block outflow therefrom. The ball may be secured by spring pressure, water pressure, and/or gravital force in the outlet opening, and may be dislodged by the animal to permit water to flow past the ball in small amounts, whereby the animal may lick or nuzzle the ball to obtain sufficient water when required.
One means of limiting leaking of metering ball assemblies in the prior art is to employ a sealed bottle, so that water discharged from the metering ball assembly must be replaced by air entering the bottle through the metering ball assembly. This arrangement creates air bubbles moving retrograde through the ball valve assembly, and contaminant particles may travel with the air bubbles and corrupt the liquid within the sealed bottle. Moreover, the sealed bottle construction must be unmounted and opened for cleaning and refilling, resulting in increased labor and expense involved in maintaining caged animals, particularly in a laboratory setting where a large number of animals are kept.
A widespread problem found in such prior art devices involves the ball valve metering devices, which are prone to fouling, clogging, and dripping. For example, the ball may accumulate superficial deposits that precipitate from the animal saliva or minerals in the water, and the precipitates disrupt the seal between the outlet opening and the ball. In addition, small changes in barometric pressure may cause a pressure imbalance between the water within the bottle and the ambient air, resulting in leakage past the ball. Leaking water may cause the animal cage to become damp or wet, and can result in a greater potential for disease in caged animals.
Other animal watering arrangements known in the prior art employ metering valves to deliver water on demand to the animal. Generally these devices include valve stems that protrude or extend from a delivery tube, so that the animal may draw water from the bottle by deflecting the valve stem. Unfortunately, animals that are bored or anxious may bite or play with the valve stem and dislodge or break it, causing replacement and maintenance problems.
Thus it is clear that an on-demand water dispensing arrangement that forms a leakproof seal yet which permits easy access is lacking in the prior art.
The present invention generally comprises a water tank for supplying water and other liquids to an animal maintained in a cage. The tank generally comprises a cylindrical container having an open upper end and a threaded lower neck opening. the upper opening is provided with a hinged, flip-top lid or closure assembly for easy filling, the closure assembly being non-sealed and generally communicating with ambient air pressure. Joined to the lower neck opening is a dispenser valve assembly that includes a threaded body received on the threaded neck, and a dispenser tube extending obliquely from the bottom of the threaded body. Within the dispenser tube, a stainless steel valve stem assembly is secured that extends to the lower opening of the dispenser tube. An animal may use its tongue to depress the valve stem assembly and cause a small amount of water to flow gravitally from the tank through the tube to the animal. The displaced liquid is replaced by air flowing into the non-sealed top opening, so that there is no retrograde air flow through the valve assembly to introduce contaminates.
The valve stem assembly is comprised of a valve stem having a pin extending distally from one end thereof. The proximal end of the valve stem includes an O-ring groove, and an annular flange extending radially as a spring keeper. The O-ring forms a seal with the coined proximal end surface of the dispenser tube, and each depression of the pin by the animal breaks the seal and permits a small amount of liquid to flow past the flange. However, the O-ring is too large to pass into the dispenser tube, and thus prevents removal of the valve assembly by an animal.
The tank is formed of a translucent polymer material such as polypropylene or the like, and is provided with a plurality of annular ridges spaced in equal increments along the vertical (axial) extent thereof. A tank mounting assembly includes a bracket having a partial annulus that defines a pair of opposed arms. The diameter of the partial annulus is approximately the same as the outer diameter of the tank, and the arms are resilient and define an opening of approximately 90xc2x0. The tank may be snap-engaged by the arms, which are dimensioned to fit between two adjacent annular ridges. The mounted height of the tank may be selected by snap-engaging the mounting bracket between selected annular ridges.
The bracket further includes a central web portion from which the two opposed arms extend. A bolt hole extends through the central web portion, and a square recess is formed in the outer surface about the bolt hole. A pair of clamping pads are provided, each comprising a rectangular block having an outer surface with a square protrusion extending therefrom that is adapted to be received in the square recess of the bracket. Each clamping pad has an inner surface including a plurality of closely adjacent parallel grooves for engaging the wires of an animal cage. A bolt hole extends through each clamping pad, centered in the square protrusion. The pads are adapted to be disposed with the inner, grooved surfaces in confronting relationship and the wires (horizontal or vertical) of the cage disposed therebetween. One clamping pad has its square protrusion socketed in the square recess of the clamping bracket, and a bolt extends through the medial web of the bracket and the two clamping pads. A wing nut secured to the bolt compresses the pads and entrains the cage wires therebetween, and secures the pads and bracket as a rigid assembly supported by the cage wires. The clamping pads may be disposed vertically or horizontally to engage horizontal or vertical wires of the cage.
The tank mounting assembly is secured to the wires of an animal cage, with the mounting bracket disposed exteriorly of the cage. The tank may be secured to the bracket at any convenient height, with the dispenser tube extending obliquely downwardly and laterally through the cage wall to be accessed by the animal. The top opening of the tank is accessible outside the cage for refilling, and the tank may easily be snap disengaged from the mounting bracket for cleaning or replacement.